Two days after North Korea's nuclear test, South Korea touted Thursday the deployment of a new cruise missile capable of hitting targets in the North "anywhere, at any time".
The defence ministry called in reporters for a special video presentation of the recently deployed missile being fired from a warship and a submarine.
"With this missile, we could hit any facility, equipment or individual target in the North anywhere, at any time of our choosing," army Major General Ryu Young-Jeo told the briefing.
Defence ministry spokesman Kim Min-Seok said the missile was accurate enough to target a particular window on a building.
It has "deadly destructive power" that could "restrain the enemy headquarters' activities" during wartime, Kim told reporters.
South Korea's military has been on a heightened state of alert ever since Pyongyang first threatened the nuclear test which was eventually conducted on Tuesday.
It was the North's third test, following previous detonations in 2006 and 2009, and seismic data suggested it was significantly more powerful.
South Korean warships and aircraft equipped with highly sensitive detection devices were deployed in the wake of the test to try and collect any traces of radioactive fallout.
Xenon gases released in the detonation could be analysed to determine what fissile material was used.
Experts are keen to confirm suspicions that the North may have switched from plutonium -- used in 2006 and 2009 -- to a new and self-sustaining nuclear weaponisation programme using uranium.
The defence ministry said any forensic material would be sent to the Korea Institute of Nuclear Safety for analysis.
The day after the test, South Korea said it would accelerate the development of longer-range ballistic missiles that could also cover the whole of North Korea.
In October last year, South Korea reached a deal with the United States to almost triple the range of its ballistic missile systems -- with Seoul arguing it needed an upgrade to counter the North's own missile development.
The United States has 28,500 troops in South Korea and guarantees a nuclear "umbrella" in case of any atomic attack. In return, Seoul accepts limits on its ballistic missile capabilities.
The defence ministry also said it would speed up the deployment of a "kill chain" system capable of detecting, targeting and destroying North Korean missiles.